4a679454d7
Primarily, this fixes a bug where a forked child of property service uses exit() instead of _exit, which has the unintended consequences of running the global destructors of init proper, which leads to unintended cleanup. Secondly, this replaces the remaining calls of exit() that really should be LOG(FATAL). Test: boot sailfish Change-Id: I779228e7d44a73186bc7685bb723c4b9278a0a2d
141 lines
4.2 KiB
C++
141 lines
4.2 KiB
C++
/*
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* Copyright (C) 2010 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "sigchld_handler.h"
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#include <signal.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <android-base/chrono_utils.h>
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#include <android-base/logging.h>
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#include <android-base/scopeguard.h>
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#include <android-base/stringprintf.h>
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#include "init.h"
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#include "property_service.h"
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#include "service.h"
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using android::base::StringPrintf;
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using android::base::boot_clock;
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using android::base::make_scope_guard;
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namespace android {
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namespace init {
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static int signal_write_fd = -1;
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static int signal_read_fd = -1;
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static bool ReapOneProcess() {
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siginfo_t siginfo = {};
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// This returns a zombie pid or informs us that there are no zombies left to be reaped.
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// It does NOT reap the pid; that is done below.
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if (TEMP_FAILURE_RETRY(waitid(P_ALL, 0, &siginfo, WEXITED | WNOHANG | WNOWAIT)) != 0) {
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PLOG(ERROR) << "waitid failed";
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return false;
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}
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auto pid = siginfo.si_pid;
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if (pid == 0) return false;
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// At this point we know we have a zombie pid, so we use this scopeguard to reap the pid
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// whenever the function returns from this point forward.
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// We do NOT want to reap the zombie earlier as in Service::Reap(), we kill(-pid, ...) and we
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// want the pid to remain valid throughout that (and potentially future) usages.
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auto reaper = make_scope_guard([pid] { TEMP_FAILURE_RETRY(waitpid(pid, nullptr, WNOHANG)); });
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if (PropertyChildReap(pid)) return true;
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Service* service = ServiceList::GetInstance().FindService(pid, &Service::pid);
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std::string name;
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std::string wait_string;
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if (service) {
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name = StringPrintf("Service '%s' (pid %d)", service->name().c_str(), pid);
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if (service->flags() & SVC_EXEC) {
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auto exec_duration = boot_clock::now() - service->time_started();
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auto exec_duration_ms =
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std::chrono::duration_cast<std::chrono::milliseconds>(exec_duration).count();
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wait_string = StringPrintf(" waiting took %f seconds", exec_duration_ms / 1000.0f);
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}
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} else {
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name = StringPrintf("Untracked pid %d", pid);
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}
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auto status = siginfo.si_status;
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if (WIFEXITED(status)) {
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LOG(INFO) << name << " exited with status " << WEXITSTATUS(status) << wait_string;
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} else if (WIFSIGNALED(status)) {
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LOG(INFO) << name << " killed by signal " << WTERMSIG(status) << wait_string;
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}
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if (!service) return true;
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service->Reap();
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if (service->flags() & SVC_TEMPORARY) {
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ServiceList::GetInstance().RemoveService(*service);
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}
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return true;
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}
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static void handle_signal() {
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// Clear outstanding requests.
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char buf[32];
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read(signal_read_fd, buf, sizeof(buf));
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ReapAnyOutstandingChildren();
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}
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static void SIGCHLD_handler(int) {
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if (TEMP_FAILURE_RETRY(write(signal_write_fd, "1", 1)) == -1) {
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PLOG(ERROR) << "write(signal_write_fd) failed";
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}
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}
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void ReapAnyOutstandingChildren() {
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while (ReapOneProcess()) {
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}
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}
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void sigchld_handler_init() {
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// Create a signalling mechanism for SIGCHLD.
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int s[2];
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if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0, s) == -1) {
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PLOG(FATAL) << "socketpair failed in sigchld_handler_init";
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}
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signal_write_fd = s[0];
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signal_read_fd = s[1];
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// Write to signal_write_fd if we catch SIGCHLD.
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struct sigaction act;
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memset(&act, 0, sizeof(act));
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act.sa_handler = SIGCHLD_handler;
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act.sa_flags = SA_NOCLDSTOP;
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sigaction(SIGCHLD, &act, 0);
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ReapAnyOutstandingChildren();
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register_epoll_handler(signal_read_fd, handle_signal);
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}
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} // namespace init
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} // namespace android
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